Overview Pin Description & Block Diagram

BD9397EFV Backlight Driver Guide This is a high-performance 6-channel LED backlight driver and DC-to-DC boost converter. It has OVP LED open and short protection. Overcurrent protection is also available. This IC is commonly used in Sony Bravia models. Other models may also use it, but we will look at it here from the Sony perspective.

Working principle how it works

BD9397EFV Backlight Driver How does this circuit work? First of all, understand that this IC is driven by PWM pulses. 19 volts are applied to it on pin 1, and it outputs 9 volts on pin 3. This same 9 volts is used to apply voltage to different pins. For example, on this pin on VREF, you can see our article on this pin. In it, we have explained the fault related to this pin.

Common fault related to specific pins

To understand this circuit, we will describe here some important pins due to which faults can be created and the entire circuit can stop working. This paragraph is based on my experience. Below we will describe the important pins, not all the pin connections that can cause problems. On which points should technicians focus their attention first?

• If the circuit is completely off, you should check the voltage at pin 1.
• Check 22 ohms between pin 5 and the main MOSFET.
• Trace pin number 7 this is the current sense pin.

Block diagram BD9397EFV

In the image below you can see the block diagram of this IC BD9397EFV. 

Common fault and diagnosis

If the symptoms are that the backlight is not turning on even though the backlight strips are correct, or the light on the screen is flickering, or the display is dim, then you should test all the resistors connected to pins 34 and 35 of the IC very carefully. The value of these resistors may increase. It would be better to test them by separating them from the circuit.

IC overheating with display

Often technicians operate the circuit by turning off the protection of this IC or by connecting the negative output lines of the IC together. Due to this, the IC starts overheating. Both these methods are very dangerous. We have seen that the PCB gets damaged due to this. A good technician fixes the root of the fault and not the wrong type of solution.

BD9397EFV Pin connection

Below you can see the complete pin connections of this IC.

Safety precaution 

Working on such a circuit requires great care. If you have to replace any part, you should have professional-level tools for it. Use good solder. Use a hot gun for small components. Use good paste. Avoid external voltage while checking the circuit. This can cause damage, especially due to overvoltage. If you work keeping your circuit theory in mind, you will achieve success.

Conclusion 

This BD9397EFV Backlight Driver Guide is a comprehensive repair guide for this specific IC. In this article, we have analyzed its common faults and pin functions. The common faults and their solutions are clearly explained to help technicians effectively troubleshoot the IC. Sony LED TV Repair Center Lahore will continue to provide such helpful articles. With your support, we will keep delivering real, practical knowledge.

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